That is something I have noticed myself on Facebook regarding most of the popular sites. There seem to be cliques of twitchers that just seem to follow each other about, the first one posts a photo and within a couple of days the same old names are posting from the same sites...and then they move on to the next species/site. My son Chris calls it 'Pokeman butterflies'...gotta get them all
Cracking Glanville undersides Wurzel
Cheers,
Neil.